Abstract
Newborns, and one, and four month olders, were presented for 90 sec with nipples varying in shape and in shape plus material. Pressure variations applied by the infant to the nipples were recorded. Overall activity as well as sucking and exploratory patterns of response were studied by observation of the polygraph records. Results suggest that a developmental trend exists, showing an increase in oral exploration and a decrease in sucking. Further, this age trend is influenced by the type of nipple. For the younger infants the addition of the novel material appears to be the basis of a differential response. For the older infants, global shape appears to be a relevant stimulus characteristic. These findings support the contention that there is a double function of the mouth: nutritive as well as perceptual. The tactual capacity revealed here is present within the first months of life and evolves relative to certain stimulus characteristics.